Contra Costa County — Historic Preservation

Last reviewed: July 6, 2026

Overview

In unincorporated areas of Contra Costa County, the county’s zoning regulations in Title 8 – Zoning touch historic resources in a focused way: primarily through floodplain management rules that define what qualifies as a “historic structure” and provide targeted relief to preserve historic character. There is no dedicated countywide “historic district” overlay found in the retrieved zoning materials; instead, historic-resource references appear in the flood hazard standards and in separate provisions that preserve designated heritage trees. Projects still proceed under base zoning, applicable design review, and other county processes.

Key rule: A variance may be issued in flood hazard areas to allow the reconstruction, rehabilitation, or restoration of a qualified historic structure if the work will not preclude the structure’s continued historic designation and the variance is the minimum needed to preserve historic character. See § 82-28.1204(1).

What the County Code Actually Regulates

• The county defines an “historic structure” for zoning purposes within its floodplain regulations. This includes properties listed on (or determined eligible for) the National Register, state inventories, or a certified local inventory/program. See § 82-28.472.
• For floodplain administration, “substantial improvement” calculations specifically exclude alterations to a qualified historic structure so long as the work does not jeopardize its historic designation. See § 82-28.512(2).
• In Special Flood Hazard Areas, the county may grant a variance to facilitate repair, rehabilitation, or restoration of a historic structure when tightly conditioned to preserve historic character. See § 82-28.1204(1); appeals follow the county’s Article 26-2.24 process referenced in § 82-28.1202(6).
• Separately, the county preserves designated heritage trees: the Planning Commission/Board may designate; removal generally requires a permit; and construction encroaching near a designated tree may require special methods. See § 816-4.404, § 816-4.602, § 816-4.802.

Projects involving historic resources must still meet any objective development standards, parking, and related procedures that apply to the underlying district. Building-code treatment of historic properties is governed separately by the California Building Standards Code (including the California Historical Building Code) and is not part of the zoning ordinance.

Key Standards and Where They Apply

District-by-District (and Area) Breakdown

Flood Hazard Management Areas (Article 82-28)

• Purpose: Regulate development in Special Flood Hazard Areas while accommodating the preservation of historic structures where feasible. See § 82-28.1204(1) and related variance/appeal provisions.
• Typical permitted “uses”: Not a use district; this article overlays base zoning with flood-resilience standards (e.g., elevation, construction, certification).
• Historic-related standards:
  • Recognizes historic structures and provides targeted relief in variance findings to preserve character/design. § 82-28.472, § 82-28.512(2), § 82-28.1204(1).
• Where it applies: Lands mapped in flood hazard zones; see general applicability referenced in § 82-28.602.
• Review body: Floodplain Administrator/Zoning Administrator; appeals to Planning Commission/Board per Article 26-2.24 as cited in § 82-28.1202(6).

Countywide Base Zoning (No specific historic overlay found)

• Purpose: Base zoning districts regulate uses, form, and site development across unincorporated areas.
• Historic-related standards: Not found in retrieved materials (no dedicated historic overlay, historic district, or landmark review standards appeared in Title 8 excerpts). Verify with the jurisdiction.
• Where it applies: All unincorporated areas under the base district regulations. Related procedures—like design review or overlay districts—may still apply depending on location and project type.

Heritage Trees (Countywide resource-specific preservation)

• Purpose: Recognize and preserve individually designated heritage trees that contribute to local heritage and landscape character. § 816-4.404, § 816-4.602, § 816-4.802.
• Typical permitted uses: Base district uses remain; the heritage-tree rules add constraints on removal and dictate construction methods near the tree.
• Key standards:
  • Designation and marking process managed by Planning Commission/Board. § 816-4.404.
  • Removal generally prohibited without a permit; emergency removals allowed with administrative clearance. § 816-4.602.
  • Encroaching work may require special construction to protect roots and canopy. § 816-4.802.
• Where it applies: Any unincorporated parcel hosting a designated heritage tree.

Process Notes and Practical Guidance

• Treat “historic preservation” in unincorporated areas as a set of targeted rules rather than a full landmark/district program in the zoning code. The most operative triggers are:
  • Is the structure a recognized “historic structure” under § 82-28.472?
  • Is the site in a flood hazard area where a tailored variance could preserve character without losing historic status (§ 82-28.1204(1); ensure the project won’t undercut the structure’s designation)?
  • Are there designated heritage trees on site that constrain removal or dictate construction means (§ 816-4.404, § 816-4.602, § 816-4.802)?
• Outside these triggers, projects rely on standard county procedures like design review, underlying development standards, and objective site regulations (e.g., parking). Any building-code flexibilities for historic resources are addressed under the California Building Standards Code, not zoning.
• Considering an ADU on or near a potential historic resource? Local historic-district standards were not found in the retrieved materials; rely on state rules for feasibility and objective standards and see California ADU law. Not found in retrieved materials for local historic-ADU specifics. Verify with the jurisdiction.

Checklist

• Confirm whether the structure qualifies as an historic structure per § 82-28.472; gather documentation of National/State/local listing or eligibility.
• Determine whether the site lies in a Special Flood Hazard Area; if so, scope floodplain requirements and whether a historic-structure variance could apply under § 82-28.1204(1).
• Ensure proposed work will not jeopardize the structure’s historic status to keep the § 82-28.512(2) exclusion available and to meet variance findings.
• Screen for designated heritage trees on or near the work area; if present, plan for permit needs and protective construction under § 816-4.404, § 816-4.602, § 816-4.802.
• Coordinate early with county staff on applicable design review and overlay districts that may layer onto the base zoning.
• Keep standard submittals current (site plan, elevations, scope) to meet objective development standards while preserving character.

Risks & Ambiguities

Plain-English Summary

In unincorporated Contra Costa County, the zoning code doesn’t set up a countywide historic overlay with design rules. Instead, it recognizes “historic structures” in flood zones and allows narrow variances to preserve their character, and it separately protects designated heritage trees. Everything else proceeds under your base zoning, any required design review, and objective standards.

Source References

• Contra Costa County Ordinance Code (Title 8 – Zoning), definition of historic structure: § 82-28.472.
• Floodplain “substantial improvement” exclusion for historic structures: § 82-28.512(2).
• Historic-structure variance conditions in flood hazard areas: § 82-28.1204(1).
• Appeals reference for floodplain actions: § 82-28.1202(6).
• Heritage tree designation and protections: § 816-4.404, § 816-4.602, § 816-4.802.

Information Gaps

• Dedicated historic preservation overlay district(s), local landmark criteria, or certificate-of-appropriateness procedures: Not found in retrieved materials. Verify with the jurisdiction.

Retrieved passages

• Contra Costa County Zoning Code Medium relevance show source text
• Contra Costa County Zoning Code (chapter which) Medium relevance show source text
• Contra Costa County Zoning Code (Chapter 26) Medium relevance show source text
• Contra Costa County Zoning Code (chapter shall) Medium relevance show source text
• Contra Costa County Zoning Code (Section 82-28.516) Medium relevance show source text
• CBC § 8 (SECTION 8-301) Medium relevance show source text
• Contra Costa County Zoning Code (Title 8) Medium relevance show source text
• Contra Costa County Zoning Code (Section 82-28.1202) Medium relevance show source text

Cited sections

• Contra Costa County Ordinance Code (Title 8 – Zoning), definition of historic structure: **§ 82-28.472**. (Title 8)
• Floodplain “substantial improvement” exclusion for historic structures: **§ 82-28.512(2)**. (§ 82-28.512)
• Historic-structure variance conditions in flood hazard areas: **§ 82-28.1204(1)**. (§ 82-28.1204)
• Appeals reference for floodplain actions: **§ 82-28.1202(6)**. (§ 82-28.1202)
• Heritage tree designation and protections: **§ 816-4.404**, **§ 816-4.602**, **§ 816-4.802**. (§ 816-4.404)
• ContraCostaCounty_ZoningCode.md

• Official Contra Costa County code library